The proposed research is designed to explore the relation between the infant's sense of self, mother and father during the transition between sensorimotor and representational thought. Interactions will be defined in two ways, by attachment classification using the Ainsworth paradigm and by differences in interactions between infants and each of their parents. Sense of self and other will be measured with scalable sequence of featural recognition and agency and infant's cognitive and affective responses to these scales will be assessed. The goals of these studies are to examine the relation between the infant's internal working models of self, other and of the relationship, to note those domains in which there is correspondence, and to note the changing relationships as a function of sensorimotor and representational conceptions of self and other. The research has been designed to provide normative data on how infant's acquire their understandings of self and other, since much of our understanding of these processes in infancy derive from retrospective work on adult patients with borderline or narcissitic personality disorders or pathological interactions between parents and their infants. As such, the research has implications for theories currently being proposed to account for developmental self-system pathology.